1. Technical Field
The present invention relates to a liquid ejecting head unit which is used in a liquid ejecting apparatus such as an ink jet type recording apparatus and a manufacturing method thereof, and particularly, to a liquid ejecting head unit capable of mounting a plurality of liquid ejecting heads with highly positional accuracy and a manufacturing method thereof.
2. Related Art
A liquid ejecting apparatus includes a liquid ejecting head capable of ejecting liquid as a droplet, and various liquids are ejected from the liquid ejecting head. For example, as a representative of the liquid ejecting apparatuses, an image recording apparatus such as an ink jet type recording apparatus (printer) can be listed, in which an ink jet type recording head (hereinafter, referred to as a “recording head”) is provided, a liquid ink is ejected as an ink droplet from a nozzle of the recording head, and the recording is performed. In addition, in recent years, the liquid ejecting apparatus has become not limited to the image recording apparatus and has been applied to various manufacturing apparatuses such as a display manufacturing apparatus.
In recent years, in the printer, a configuration has been adapted, in which a recording head including a nozzle group, which is constituted by installing nozzles in a plurality of rows, is fixed side by side in a plurality to a head fixing member such as a sub-carriage and configured as one head unit (for example, refer to JP-A-2008-273109). The sub-carriage is a frame-shaped member so that the portion of the sub-carriage to which a plurality of the recording heads is mounted is opened. In addition, each recording head is fixed to the sub-carriage through screw-fastening in a state of being positioned with respect to the sub-carriage.
Here, in the printer which is configured so as to perform a recording operation while relatively reciprocating the recording head and a recording medium, a configuration is suggested in which each recording head is mounted on the sub-carriage so that arrangement of ink colors assigned to each nozzle row of the recording head is a symmetric positional relationship in the same direction from a center in a juxtaposed direction of the recording head in the sub-carriage. In the above configuration, two recording heads including the nozzle row of the same color are provided as a set, each recording head constituting the set is disposed on the sub-carriage so as to be in a symmetric positional relationship in the same direction from the center of the juxtaposed direction of the head. By adopting the above-described configuration, a landing sequence of the ink of each color can be aligned with respect to the recording medium at a forward path and a return path.
If the landing sequences of the ink of each color are different from each other with respect to the recording medium in the reciprocation, color tones of a portion in which dots of different colors are overlapped are different in the reciprocation. For example, a color tone of a portion in which a cyan dot formerly formed and a magenta dot subsequently formed are overlapped and a color tone of a portion in which a magenta dot formerly formed and a cyan dot subsequently formed are overlapped are different from each other. Thereby, there is a concern that an adverse effect may occur in the image quality of the recording image or the like. On the other hand, according to the configuration, due to the fact that the landing sequence of the ink of each color is aligned with respect to the recording medium in the forward path and the return path, the sequence in which dots of different colors are overlapped is also aligned in the reciprocation, and therefore, deterioration of the image quality of the recording image or the like can be suppressed.
However, for example, in a configuration in which nozzles of a recording head are formed through plastic working by using a punch, inclination of a center axis of the nozzle with respect to a nozzle formation surface may occur. Even when the mounting position of the recording head with respect to the sub-carriage is adjusted and mounted so that the nozzle position of each recording head is disposed in a defined position, in a case where the inclination of the nozzle is different for each recording head, a flight direction of the ink also varies for each recording head. As a result, variation in the landing position of the ink with respect to a recording medium such as a recording sheet occurs, and there is a concern that image quality of a recording image or the like may deteriorate. In particular, as the above-described configuration, if variation of the landing position occurs in the recording heads which are symmetrically disposed to the sub-carriage and constitute a set of the same color, more serious adverse effect may occur in the image quality of the recording image or the like.
On the other hand, a method is considered in which the mounting position of the recording head is adjusted with respect to the sub-carriage so that ink is actually ejected from the nozzles of each recording head to the recording medium and the landing position of the ink corresponds to a landing position which is a design target. However, when compared to the method in which the mounting position of the recording head on the basis of the position of the nozzles is adjusted, the adjusting method needs many more adjusting times, and there is a problem in that a disadvantage from the standpoint of productivity occurs. From reasons similar to the above matters, time is needed even when the position of the recording head is readjusted due to after-service or the like, and the operating ratio is decreased.
In addition, the above problems are generated in not only an ink jet type recording apparatus on which the recording head ejecting ink is mounted but also other liquid ejecting head units adopting a configuration which fixes a plurality of liquid ejecting heads to a head fixing member and a liquid ejecting apparatus including the liquid ejecting head unit.